Since the beginning of mankind, human beings have strived to pass on their thoughts and knowledge to other people and to future generations. In this respect, the cultural role played by paper has been immense: paper is used for drawings, books, archival documents, photographs, prints, and so forth. Paper was first made in China around 105 AD, and its history can be roughly divided into two major periods: before the 19th century, when paper was made by hand, cellulose from linen and cotton rags was used as the raw material; from the 19th century onwards, when paper was machine-made from wood pulp, paper has contained several other components in addition to cellulose; these include lignin, hemicellulose and pectin. Furthermore, paper is often coated with sizes (the sizing of paper is a process that renders the sheets impervious to ink) such as gelatine, or with minerals, pigments and other substances to impart desirable properties. Libraries, archives and museums preserve paper material, and such material is at risk of deterioration and needs to be protected from physicochemical and biological agents. In many cases, microbial processes have been implicated in paper deterioration.
Scripta manent? Assessing microbial risk to paper heritage. Trends in Microbiol. Oct 22 2010
Paper, like all other cultural heritage materials, degrades over time, but conservation slows down the rate of its deterioration. There is a long history of cooperation between microbiologists and conservators of libraries and archival materials, but current approaches addressing paper deterioration need urgent reassessment to take full advantage of modern microbiological methodologies. This article discusses what we believe are the current priority research areas in assessing microbial risk to paper heritage, and reports studies on a 13th century Italian manuscript and on Leonardo da Vinci’s Atlantic Codex which illustrate the problems and challenges encountered when dealing with microbial investigations of paper artworks. The potential of using a more advanced microbiological approach is highlighted.